Aureobasidium is ubiquitous in nature and can infect human occasionally. The pathogenic species include A. pullulans, A. melanogenum, A. proteae and A. mansoni. There are a variety of clinical manifestation types, such as fungemia, peritonitis, skin infection, meningitis, spleen abscess, pneumonia, scleritis, keratitis, lymphadenitis and onychomycosis. Aureobasidium infections are difficult to diagnose and easily misdiagnosed. This literature review is based on related literature in Medline and Chinese literature database, concerning regional distribution, risk factors, clinical manifestation, pathogenic species, antifungal susceptibility, diagnosis and treatment of Aureobasidium infections.
The mitochondrial genome of Penicillium canescens SFY00C3 isolated from Ophiocordyceps gracilis was determined and its composition characteristics were analyzed. The phylogenetic relationship between the genome and Penicillium species was explored. The results showed that the mitochondrial genome of P. canescens SFY00C3 was a circular DNA molecule with a length of 28 301 bp, encoding 42 genes (15 protein coding genes, 2 rRNA genes and 25 tRNA genes). Its base composition had significant A-T bias. All of the 25 tRNA genes could form a typical cloverleaf structure with 32 G-U mismatches. Gene rearrangement of mitochondrial genome was found by collinearity analysis among Penicillium species. The Ka/Ks values of 14 protein coding genes were less than 1, indicating that they were subjected to purification selection pressure. Phylogenetic analysis showed that SFY00C3 was an independent branch in Penicillium and should be the sister of the ancestors of six species of Penicillium. This finding enriched the mitochondrial genome sequence information of P. canescens, and provided basic data for phylogenetic analysis, resource protection and genetic diversity of Penicillium.
The nematode-trapping Arthrobotrys oligospora is a carnivorous ascomycetous fungus, with mycelia can transformable to a variety of finely trapping devices to capture nematodes. The fungus can be used as model samples in adaptative evolution researches and as biological control agents against parasitic nematodes. The use of the mitochondrial gene, cytochrome c oxidase subunit I gene (COX1), as molecular marker for species identification in the kingdom Fungi was debated for a long time. In order to explore the degree and range of heterogeneity in each generation of the same strain, the COX1 gene of A. oligospora YMF1.03037 different single spore isolates was amplified and compared. The results showed that the SNPs existed inter- and intra- generations and inter- and intra- lineages, but genetic variance among generations is greater than that among lineages. Most private alleles are found in F3, which have not been found in the parental generation, indicating that there might be potential other genotypes that we haven't explored. During subsequent amplification, new genotypes that were not previously amplified might appear. Recombinant analysis showed that recombination events among SNP sites were of frequent occurrence, providing the first robust evidence of heteroplasmy in the mitochondrial genomes of the nematode-trapping fungus A. oligospora. In addition, heterogeneity may be caused by gene recombination and multiple copy nature of COX1 gene. This study provides a scientific basis for further revealing the role of COX1 gene in the evolution of nematode-trapping hyphomycetes and evaluating the effect of mitochondrial gene in the molecular identification of filamentous fungi.
Zn(II)-Cys(6) proteins are zinc-finger type transcription factor that exist only in fungi, which play important roles in biological processes. Their precise function is still unclear in Trametes gibbosa. In this study, the transcriptome of T. gibbosa treated with sawdust was constructed to discover Zn(II)-Cys(6) transcription factor differentially expressed genes for exploring the function and role of the transcription factor of the fungus in a woody environment. The lignin degrading enzyme activity of T. gibbosa was tested under sawdust treatment, then the RNA of hyphae aged 0, 3, 5, 7, and 11 d was extracted, and the transcriptome of the hyphal samples was sequenced using HiSeq high-throughput sequencing technology. COG, GO, Pfam, and Swiss databases were used for functional annotation analysis. All Zn(II)-Cys(6) protein genes were screened out and seven differentially expressed genes were further screened out for analysis. Differentially expressed gene structures were analysed, and a heat map of the expression trends was constructed. A variety of biological characteristics, physical and chemical properties, secondary and tertiary structures, and hydrophobicity was predicted. Phylogenetic trees were constructed and the motif sequences were predicted to analyze the evolutionary relationship among the seven differentially expressed genes, and RT-qPCR was performed on these genes to further verify the results of the transcriptome sequencing. Seven Zn(II)-Cys(6) transcription factor differentially expressed genes in T. gibbosa were analyzed and identified and these results provide a reference for subsequent studies examining the function and expression of Zn(II)-Cys(6) transcription factors.
Coding product of FADB gene in Aspergillus fumigatus is FAD binding oxidoreductase, which may be involved in the respiration of fungi. In this study, FADB gene knockout strain of A. fumigatus is constructed by cloning FADB gene, and mechanism of FADB gene responsible for the changes of drug sensitivity, osmotic pressure and oxidative stress sensitivity of A. fumigatus is investigated. The knockout box of FADB gene is constructed by high throughput gene replacement method, and the corresponding FADB knockout strain ΔFADB of A. fumigatus is selected. The changes of drug sensitivity, oxidative pressure and osmotic substance sensitivity of the mutant and wild type AF293 are observed. The results of detecting the sensitivity of ΔFADB to three kinds of azole by E-test prove that the sensitivity of ΔFADB to posaconazole is increased. In the cultivating tests under osmotic and oxidative pressure, ΔFADB was more sensitive to the oxidants D-sorbitol and menadione than the wild type AF293. ΔFADB produced more reactive oxygen species than wild AF293 when posaconazole was added. The FADB gene of A. fumigatus might play a role in the antifungal mechanism of posaconazole, and the induction of oxidative stress may be one of the mechanisms of antifungal drugs against fungi. The results of this study suggest that FADB might involve in azole resistance in A. fumigatus, and further mechanistic investigations is required in the future.
Beauveria bassiana, as a hyphomycete pathogenic fungus, is widely used in the control of agricultural and forestry insect pests. However, the changeable environment in the field limits the effectiveness of the fungal agent. In addition, the environment in vivo of the host also affects the proliferation and infection rate of the fungus. In order to study the balance ability of the fungus to environmental pH and trace elements, the relationship between zinc-responsive transcriptional activator ZafA and B. bassiana growth and reproduction, stress resistance, virulence and zinc utilization was preliminarily explored. The results showed that deletion of zafA resulted in reduction of the ability of fungal growth and reproduction and spore germination, and the sensitivity to oxidation, hyperosmotic, cell wall interfering agents and UV stress increased, bringing about the decline of virulence and expression level of related trait genes. The knockout strains could not grow without zinc ion. The expression levels of zafA and zinc ion transporter coding genes zrf1-8 were affected by pH and zinc ion concentration. Thus, zafA not only restricts the utilization of zinc ion of B. bassiana, but also affects the stress resistance and virulence of the fungus. This study provides a new evidence for improving environmental adaptability and virulence of the fungi used for biocontrol.
The relationship between the main components of the circadian oscillator of circadian clock constitutes a transcription-translation negative feedback loop which regulates the physiology, biochemistry, growth and development of the organisms. The mycelium of Cordyceps militaris was treated with different time of blue light irradiation and proteasome inhibitor MG132, and the transcriptional changes of three genes Cmfrq, Cmwc-1 and Cmwc-2, the main components of the circadian oscillator, were analyzed by real-time fluorescent PCR, in order to determine the relationship and variation rule of the three genes in C. militaris. Under the condition of continuous darkness, MG132 has a relatively notable impact on the transcription levels of Cmfrq, but a limited impact on the transcription levels of Cmwc-1 and Cmwc-2. In the process of dark culture, under the condition of 2 h blue light interruption, the Cmfrq transcription level decreased sharply in the later period of culture without MG132 treatment, while the transcription level of Cmwc-1 increased sharply. The Cmfrq and Cmwc-1 transcription levels showed the characteristics of circadian oscillator negative feedback regulation. The transcriptional level of Cmfrq is affected by nutrient conditions, and the addition of MG132 made Cmfrq transcription insensitive to nutrient changes. Under the condition of continuous blue light irradiation, the Cmfrq transcription level also showed a sharp decline in the later period without MG132 treatment, and Cmfrq transcription was more sensitive to MG132 treatment. With or without MG132 treatment, the three genes did not reflect the characteristics of circadian oscillator negative feedback loop. Under the cycle alternation of blue light 12 h and dark 12 h, the transcriptional levels of these three genes were inconsistent between the two cycles. When continuous darkness entered the cycle alternation, Cmfrq transcriptional levels were from high to low. In the second cycle, the transcription levels of Cmwc-1 and Cmwc-2 were very low, but MG132 led to the increase of the transcription levels of Cmwc-1 and Cmwc-2. Compared with dark conditions, blue light treatment can lead to increase Cmfrq transcription levels. The transcription level of Cmwc-1 is very low in most cases, indicating that this gene is a key gene in the circadian oscillator.
Ganoderma species, generally used as traditional medicine in China, have considerably high medicinal and economic values. A wild Ganoderma isolate collected from Nanning, Guangxi Zhuang Autonomous Region was purified and identified as Ganoderma sichuanense by molecular biology analysis based on ITS sequences, and its biological characteristics and antioxidant activities were studied. The effects of different carbon and nitrogen sources, inorganic salts, pH, and temperature on the mycelial growth rate under solid cultivation were investigated. Single-factor tests were conducted on the five factors, among which four factors were screened and subjected to an orthogonal test. The results showed that the optimal carbon and nitrogen sources, and inorganic salt for the mycelial growth of wild G. sichuanense were maltose and beef extract, and KH2PO4, respectively, under conditions of pH 7.0 at 30 °C. Further optimization based on orthogonal test proved that the optimal composition of the culture medium was maltose 30.0 g/L, beef extract 5.0 g/L, KH2PO4 1.0 g/L, and pH 6.0. The contents of polysaccharide, triterpenoid, polyphenol, and ascorbic acid, the variation of superoxide dismutase activity, and scavenging ability to hydroxyl radicals were determined during the liquid cultivation. It was found that the wild G. sichuanense owned antioxidant activity.
Disease prevention and growth promoting effect of Gleditsia sinensis fermentation product on Dictyophora rubrovolvata, the local specialty of Guizhou Province, were investigated. The pathogenic bacterium was isolated in the laboratory and the plate confrontation experiment was carried out. Four treatments were designed in the field experiment: conventional treatment without pesticide, Bacillus amyloliquefaciens HN11 treatment, G. sinensis powder treatment and G. sinensis fermentation product treatment. The control effect was investigated, the size and number of fungus eggs (young basidiocarp) were measured, and the changes of soil microbial community were detected. A pathogen was isolated from the diseased tissue and identified as Enterobacter cloacae. The field control effect of G. sinensis fermentation product on diseased D. rubrovolvata reached 77.86%, and D. rubrovolvata field growth area increased by 61.22%. As compared with untreated control, the relative abundance of D. rubrovolvata in the soil treated with G. sinensis fermentation product reached the highest of 25.83%. The G. sinensis fermentation product can effectively prevent and control disease of D. rubrovolvata, promote the growth of D. rubrovolvata eggs, reduce the dosage of chemical pesticides, stimulate the ecological cycle, ensure safety of edibles, and improve the comprehensive benefits of G. sinensis and D. rubrovolvata industries.
Two specimens of wild macrofungi collected from northwestern Yunnan were identified as Flammulina rossica and F. filiformis based on molecular phylogenetic (internal transcriptional spacer) analysis and morphological characters. The isolated strains Mdr-02 and Mdr-09 were used to study their biological characteristics and domestication. The effects of carbon source, nitrogen source, temperature, pH value and inorganic salt on growth of the mycelium were investigated by single factor test and three optimal levels were selected for orthogonal test to investigate effects of different culture conditions on the growth of mycelia. The results indicated that the optimal carbon source for the growth of F. rossica was malt powder, and the best nitrogen source was bean cake powder, and the best calcium carbonate was inorganic salt. Incubation under pH 6.0 and 24 °C showed optimal growth of the mycelia. The most suitable carbon source for F. filiformis was malt powder, the best nitrogen source was yeast powder, and the best inorganic salt was magnesium sulfate. Incubation under pH 6.0 and 24 °C showed optimal growth of the mycelia. F. rossica was successfully domesticated for the first time and a new domesticable F. filiformis strain was obtained. These results will advantage the development of germplasm resources and the breeding of new cultivated varieties of Flammulina species.
The nutritional and environmental characteristics of a wild Clitocybe fragrans obtained from Pingquan City in Hebei Province were studied. The effects of carbon source, nitrogen source, C/N, and inorganic salt on the mycelial growth were investigated by single factor test and optimized by orthogonal experiments. The results revealed that the optimum carbon source, nitrogen source, C/N and inorganic salt were sucrose, yeast extract, 40:1, and magnesium sulphate respectively. The culture medium formula was as follows: sucrose 17.3 g, yeast extract 1.8 g, potassium dihydrogen phosphate 3 g, anhydrous magnesium sulfate 1.5 g, agar 20 g, and water 1 L. The mycelia grew well at pH 5.0-5.5 and incubation temperature of 19-25 °C under dark condition. The domestic cultivation of the mushroom was executed successfully. The suitable stock culture medium for propagated cultivation was composed of 100 g of compost substrate (boiled juice), 200 g of potato (boiled juice), 20 g of glucose, 3 g of potassium dihydrogen phosphate, 3 g of peptone, 1.5 g of anhydrous magnesium sulfate, 20 g of agar and 1 L of water. The mother spawn medium was composed of sorghum 98%, glucose 1%, and gypsum 1%. The spawn substrate was composed of 98% compost substrate, 1% gypsum and 1% glucose with 55% moisture capacity. Using method of sack cultivation, the mycelia were sackful in 35-40 days after inoculation. The primordia were formed 8-10 days later, and grew into fruit bodies after 7-8 days.
Nitrogen source types and concentration generally affect the mycelial growth and metabolism of Pleurotus ostreatus. Nitrogen deficiency and excessive accumulation have adverse effect on the growth of P. ostreatus. In this study, ammonium phosphate was used as sole nitrogen source and the optimal concentration of ammonium phosphate for mycelial growth and enzymolysis of lignocellulose of P. ostreatus were determined. Results showed that the hyphae grew best at ammonium phosphate concentration of 10-20 mmol/L. In comparison with nitrogen deficiency control, carboxymethyl cellulase activity increased significantly and reached the highest at ammonium phosphate concentration of 10 mmol/L. Filter cellulase activity increased significantly and reached the highest at ammonium phosphate concentration of 5-10 mmol/L. Xylanase activity increased significantly and reached the highest at ammonium phosphate concentration of 40 mmol/L. Laccase activity increased significantly and reached the highest at ammonium phosphate concentration of 10 mmol/L. High enzyme activity in P. ostreatus is beneficial to degradation and utilization of substrate.
Morchella is a widely distributed edible and medicinal fungal genus all over the world. More and more attentions have been paid to the accumulation of cadmium in Morchella. However, the mechanism of cadmium accumulation is not clear. In this study, Morchella spongiola was cultured in 0-5.0 mg/L cadmium media, and the physiological and biochemical indexes such as mycelial growth rate, malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione (GSH), ascorbic acid (ASA) and cellular cadmium accumulation were measured in order to clarify the mechanism of antioxidant defense response of M. spongiola to Cd toxicity. With the increase of cadmium concentration, the mycelial growth of M. spongiola showed a bimodal response of “rising-descending-rising-descending”, in which 0.15, 0.90 and 1.50 mg/L were the key inflection points of cadmium concentration in mycelial growth. The oxidative damage caused by cadmium stress was positively correlated with cadmium initial concentration, and the content of MDA and H2O2 increased greatly after 3 d stress. The content of MDA and H2O2 in the 5.0 mg/L treatment group were 5.80 and 6.08 times higher than that in the control group, respectively. The effects of cadmium concentration and stress time on anti-oxidation system were different, and the activities of SOD and POD increased gradually with the increase of cadmium concentration. In the range of 1.5-5.0 mg/L cadmium concentration, the activities of SOD and POD increased by 1.96 times and 2.15 times, respectively. The activities of CAT and GSH-Px reached the maximum at cadmium concentration of 0.15 mg/L, and then the enzyme activity was inhibited with the increase of cadmium concentration. The content of GSH and ASA increased in a concentration-dependent manner at the initial stage of cadmium stress, and then decreased after 5 d cadmium stress. The extracellular cadmium accumulation increased with the increase of exogenous cadmium concentration, but the intracellular cadmium content did not increase significantly in the range of 1.5-5.0 mg/L. The dynamic trend and internal change law of M. spongiola in response to cadmium stress concentration and stress time were studied systematically for the first time, and this study laid a foundation for the further study of the interaction between Morchella and heavy metals, advantaging the application in bioremediation of cadmium-contaminated wastewater by using mycelia of Morchella.
Three species of Talaromyces sect. Islandici new to China are reported in this paper, namely T. acaricola, T. radicus and T. tratensis, which are identified by morphological observation and molecular phylogenetics analysis based on CaM, Rpb2 and rDNA ITS1-5.8S-ITS2 sequences. Talaromyces acaricola has a restricted growth rate, forming velutinous colonies with sparse gray-green conidia en masse and pale green-yellow mycelium on MEA; it produces loosely-positioned biverticillate, terverticillate and irregular penicilli with fusiform to ellipsoidal, smooth-walled conidia. Talaromyces radicus has a low growth rate but grows normally at 37 °C, and forms compact floccose colonies with sparse, grayish conidia en masse and green-yellow mycelium; its penicilli are biverticillate and compact with cylindrical to acerose phialides and ellipsoidal, smooth-walled conidia. Talaromyces tratensis grows slowly without sporulation, producing orange-yellow mycelium and gymnothecia, and bearing ellipsoidal, smooth-walled to slightly roughened ascospores.
